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Question-121817




Question Number 121817 by shaker last updated on 12/Nov/20
Answered by liberty last updated on 12/Nov/20
 lim_(x→1)  (((nx^m −n−mx^n +m)/(x^(m+n) −x^n −x^m +1)) ) =    lim_(x→1)  (((mn(x^(m−1) −x^(n−1) ))/((m+n)x^(m+n−1) −nx^(n−1) −mx^(m−1) )))=  lim_(x→1) (((mn((m−1)x^(m−2) −(n−1)x^(n−2) ))/((m+n)(m+n−1)x^(m+n−2) −n(n−1)x^(n−2) −m(m−1)x^(m−2) )) )=     ((mn(m−n))/(m^2 +2mn+n^2 −m−n−n^2 +n−m^2 +m))  = ((mn(m−n))/(2mn)) = ((m−n)/2). ▲
limx1(nxmnmxn+mxm+nxnxm+1)=limx1(mn(xm1xn1)(m+n)xm+n1nxn1mxm1)=limx1(mn((m1)xm2(n1)xn2)(m+n)(m+n1)xm+n2n(n1)xn2m(m1)xm2)=mn(mn)m2+2mn+n2mnn2+nm2+m=mn(mn)2mn=mn2.
Answered by bemath last updated on 12/Nov/20
let x = 1+ w ; w→0   lim_(w→0)  ((n/((1+w)^n −1)) − (m/((1+w)^m −1)))  = lim_(w→0) ((n/(nw+((n(n−1))/2)w^2 )) − (m/(mw+((m(m−1))/2)w^2 )))  = lim_(w→0) (((2n)/(2nw+n(n−1)w^2 )) − ((2m)/(2mw+m(m−1)w^2 )))  = lim_(w→0) (((2n(2mw+m(m−1)w^2 )−2m(2nw+n(n−1)w^2 ))/((2nw+n(n−1)w^2 )(2mw+m(m−1)w^2 ))))  = lim_(w→0) (((4mn+2mn(m−1)w−4mn−2mn(n−1)w)/((2n+n(n−1)w)(2mw+m(m−1)w^2 ))))  = lim_(w→0) ((((2mn(m−1)−2mn(n−1))w)/((2n+n(n−1)w)(2m+m(m−1)w)w)))  = lim_(w→0) (((2mn(m−1−n+1))/((2n+n(n−1)w)(2m+m(m−1)w)))  = lim_(w→0) (((2mn.(m−n))/(2n.2m))) = ((m−n)/2)
letx=1+w;w0limw0(n(1+w)n1m(1+w)m1)=limw0(nnw+n(n1)2w2mmw+m(m1)2w2)=limw0(2n2nw+n(n1)w22m2mw+m(m1)w2)=limw0(2n(2mw+m(m1)w2)2m(2nw+n(n1)w2)(2nw+n(n1)w2)(2mw+m(m1)w2))=limw0(4mn+2mn(m1)w4mn2mn(n1)w(2n+n(n1)w)(2mw+m(m1)w2))=limw0((2mn(m1)2mn(n1))w(2n+n(n1)w)(2m+m(m1)w)w)=limw0(2mn(m1n+1)(2n+n(n1)w)(2m+m(m1)w)=limw0(2mn.(mn)2n.2m)=mn2

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